1.
Let A={1,6,11,16,…}A = \{1, 6, 11, 16, \ldots\} and B={9,16,23,30,…}B = \{9, 16, 23, 30, \ldots\} be the sets consisting of the first 2025 terms of two arithmetic progressions. Then n(A∪B)n(A \cup B) is